This invention relates generally to data storage systems for handling and storing data cartridges, such as optical disk or magnetic tape cartridges, and more specifically to systems for identifying the various data cartridges stored therein.
Many different types of data storage systems exist and are being used to store data cartridges at known locations and to retrieve desired data cartridges so that data may be written to or read from the data cartridges. Such data storage systems are often referred to as autochanger data storage systems, or simply, autochangers.
A typical autochanger data storage system may include one or more different types of cartridge receiving devices for holding the various data cartridges. For example, one type of cartridge receiving device may comprise an individual cartridge storage location or slot (for holding a single data cartridge) or a cartridge storage rack or xe2x80x9cmagazinexe2x80x9d (for holding two or more data cartridges). Another type of cartridge receiving device may comprise a cartridge read/write device for reading data from or writing data to the data cartridge. The cartridge storage slots or magazines serve to provide storage locations for the data cartridges and are commonly arranged so that they form one or more vertical stacks, although other configurations are possible. The cartridge read/write device may be located at any convenient location within the data storage system.
The autochanger or data storage system may also be provided with a cartridge handling system for transporting the data cartridges between the various cartridge receiving devices, e.g., between the cartridge storage locations and the cartridge read/write devices. A typical cartridge handling system may include a cartridge engaging assembly or xe2x80x9cpickerxe2x80x9d for engaging the various data cartridges contained in the cartridge receiving devices, as well as a positioning device for moving the cartridge engaging assembly among the various cartridge receiving devices.
Autochangers or data storage systems of the type described above are usually connected to a host computer system (not shown) which may access or store data on the data cartridges. For example, if the host computer system issues a request for data contained on a particular data cartridge, a control system associated with the autochanger actuates the positioning system to move the cartridge engaging assembly or xe2x80x9cpickerxe2x80x9d along the cartridge storage locations until the cartridge engaging assembly is positioned adjacent the desired data cartridge. The cartridge engaging assembly may then remove the data cartridge from the cartridge storage location and carry it to the cartridge read/write device. Once properly positioned adjacent the cartridge read/write device, the cartridge engaging assembly may insert the selected data cartridge into the cartridge read/write device so that the host computer may thereafter read data from or write data to the data cartridge. After the read/write operation is complete, the cartridge engaging assembly may remove the data cartridge from the cartridge read/write device and return it to the appropriate cartridge storage location.
Since most such data storage systems contain a large number of individual data cartridges, some means is usually provided to allow the data storage system to identify and locate the desired data cartridge. Simpler data storage systems require the system operator to manually inventory the data cartridges. In such a manual operation, the system operator usually first identifies each cartridge, then programs the data storage system with the identity and storage location of each of the individual data cartridges. More sophisticated systems are capable of automatically performing the inventory operation. For example, a common type of automated inventory system provides each of the data cartridges with a machine-readable code (e.g., a bar code label) that uniquely identifies each data cartridge. The data storage system is then provided with a suitable code reader system (e.g., a bar code reader) to read or identify the code for each cartridge. Thus, when the data storage system is first placed in operation, the reader system will examine each data cartridge to ascertain its identity, then instruct the data storage system as to its location. This procedure is repeated for each individual cartridge. Once the data cartridges have been identified and inventoried, the data storage system will be placed in service.
It is often necessary or desirable for a system operator to periodically access one or more of the data cartridges contained within such a data storage system. For example, it may be necessary for the system operator to remove certain of the data cartridges from time to time if they become filled with data that is to be archived at another location. The system operator may then replace the filled data cartridges with blank data cartridges. In another situation, the system operator may desire to remove one or more of the data cartridges and replace it or them with a substitute data cartridge or cartridges containing different data.
Regardless of the reason for adding, removing, or replacing one or more of the data cartridges, the data storage system will need to re-inventory the data cartridges before it can be returned to operation. While the need to re-inventory the data cartridges may not be particularly burdensome in some cases, it can be particularly disadvantageous if the data cartridges are exchanged frequently or if the data storage system contains a large number of data cartridges.
A data storage system according to one embodiment of the present invention comprises a plurality of cartridge receiving devices provided within the data storage system. A cartridge engaging apparatus having a cartridge access side and a back side is mounted within the data storage system so that the cartridge engaging apparatus moves along a displacement path. The arrangement of the plurality of cartridge receiving devices and the displacement path is such that at least one of the plurality of cartridge receiving devices is located opposite the back side of the cartridge engaging apparatus. An information reader mounted to the cartridge engaging apparatus reads cartridge information provided on a data cartridge located adjacent the back side of the cartridge engaging apparatus.
Also disclosed is a method for detecting cartridge information provided on a data cartridge stored within a data storage system that comprises the steps of: Providing the data storage system with a cartridge engaging apparatus that moves along a displacement path so that at least one data cartridge is located opposite the back side of the cartridge engaging apparatus; providing an information reader to the cartridge engaging apparatus so that the information reader can read cartridge information provided on a data cartridge located adjacent the back side of the cartridge engaging apparatus; moving the cartridge engaging apparatus so that the back side is adjacent a data cartridge; and operating the information reader to read the cartridge information provided on the data cartridge.